|Publication number||US7219913 B2|
|Application number||US 10/433,061|
|Publication date||May 22, 2007|
|Filing date||Nov 30, 2001|
|Priority date||Dec 1, 2000|
|Also published as||CA2436907A1, CA2436907C, CN1270932C, CN1486259A, DE60143056D1, EP1406807A1, EP1406807A4, EP1406807B1, US20040104555, WO2002044005A1|
|Publication number||10433061, 433061, PCT/2001/1559, PCT/AU/1/001559, PCT/AU/1/01559, PCT/AU/2001/001559, PCT/AU/2001/01559, PCT/AU1/001559, PCT/AU1/01559, PCT/AU1001559, PCT/AU101559, PCT/AU2001/001559, PCT/AU2001/01559, PCT/AU2001001559, PCT/AU200101559, US 7219913 B2, US 7219913B2, US-B2-7219913, US7219913 B2, US7219913B2|
|Original Assignee||Trackaxle Pty Ltd.|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (56), Non-Patent Citations (3), Referenced by (9), Classifications (11), Legal Events (5)|
|External Links: USPTO, USPTO Assignment, Espacenet|
This application is the national phase under 35 U.S.C. §371 of PCT International Application No. PCT/AU01/01559 which has an International filing date of Nov. 30, 2001, which designated the United States of America.
This invention relates to articulated vehicles of the type having a prime mover, or tractor, and one or more trailers.
An often-seen vehicle in this class is the so-called “semi-trailer”, having a prime mover with a single trailer, the trailer usually being longer than the prime mover. The trailer typically has one, two or three non-steerable axles adjacent to its rear end and a turntable at its front end which mates with a cooperating arrangement (sometimes termed a “fifth wheel”) on the prime mover so that the trailer can articulate about a substantially vertical axis of the prime mover for turning.
A number of problems arise with articulated vehicles of this type. One of these is manoeuvring. A significant width of road is required for turning corners, for example, by comparison with shorter non-articulated vehicles, and driver skill requirements may be high, because a trailer's fixed wheels generally “off track”, i.e. fail to follow the path taken by the wheels of the prime mover. At least at comparatively low speeds, the trailer wheels normally track inside the path of the prime mover. These problems can be particularly acute on city roads as a turning vehicle in one lane may encroach on another lane. At high speeds tracking of the trailer wheels outside the path of the prime mover is known. However, the problem of off-tracking at comparatively low speeds is the more practically significant one, and much effort has been expended in trying to provide practical solutions.
A further problem is tyre wear due to scuffing or scrubbing on the road surface. When multiple, parallel axles are provided on the trailer, as is common, it is not possible for the axes of rotation of the trailer's wheels to converge at the centre of the trailer's turning circle, so that tyre scrubbing is inevitable. Apart from excessive tyre wear, scrubbing, leads to increased fuel consumption, and may also lead to poorer braking and roadholding.
A still further problem with semi-trailers is manoeuvrability when reversing. In tight quarters particularly, it can be difficult to manoeuvre such a vehicle as required.
The present invention is directed to at least alleviating the problems set out above. Other attempts have been made to address these problems, and many of these suffer from a further problem, namely the need for major modifications to the prime mover, by comparison with a “standard” prime mover such as would be used for conventional semi-trailers. As it is commonly required that a given trailer be towed by many different prime movers, systems not requiring major modifications to the prime mover are desirable, and the present invention provides such a system.
It should be noted that the off-tracking problem arises with vehicles having multiple trailers behind a prime mover. The invention disclosed below is also applicable in some aspects to such vehicles. Two-trailer articulated vehicles are often used in metropolitan areas, and vehicles having three or more trailers are also known, although due to their limited manoeuvrability they are normally confined to non-metropolitan roads and off-road applications.
Various approaches have been proposed for solution, or partial solution, of the closely related problems of tracking and tyre scrubbing, but a range of disadvantages appear to have prevented their widespread adoption for ordinary articulated vehicles.
One approach to reducing tyre scrubbing on trailers, but which is of very limited usefulness in improving tracking, is to provide for some wheel/axle assemblies to have fixed (non-steerable) wheels but to be free to pivot as a whole about a vertical axis placed ahead of the axle in the direction of travel, thereby to have a castoring action. See for example Sibbald, PCT/AU94/00743, and Becker and Ennor, Australian Patent No. 664919. Arrangements in this class must have some means for locking the wheel/axle assemblies in a straight-ahead orientation, or for shifting the vertical axis behind the axle, to allow for reversing. Castoring wheel assemblies have not found significant favour in practice.
The problem of reducing off-tracking of trailers has been most commonly addressed by providing arrangements whereby at least some of their wheels are “steered” during turns in an opposite sense to the steering of the prime mover. That is, if the prime mover begins a turn to the right, some wheels adjacent to the rear of the trailer are oriented to displace the rear of the trailer to the left, i.e. to the outside of the turn. If the degree of such orientation is suitably chosen, the rear of the trailer may be caused to follow substantially the path taken by the prime mover. Many of these arrangements also tend to reduce the problem of tyre scrubbing, although the degree of reduction varies widely among the various proposals.
Some of these improved tracking systems actively orient the trailer wheels, or some of them, in a way responsive to articulation between the trailer and the prime mover or responsive to steering of the prime mover's front wheels. These systems generally require a prime mover significantly different from a conventional one. These vary from very simple mechanical systems such as that of Humes, U.S. Pat. No. 3,533,644, to more complex mechanical and/or hydraulically actuated systems, for example, the system described by Kramer, U.S. Pat. No. 4,982,976.
In another class of improved tracking arrangements, reliance is placed on the tendency of the trailer's wheels to continue moving forward as the front of the trailer is displaced laterally in a turn. The consequent difference between the original path of these wheels and the new path of the trailer provides an input which can be harnessed to orient the trailer wheels to the degree required for correct tracking of the prime mover's path. Curry (U.S. Pat. No. 3,899,188) describes such a system with a fixed wheel/axle assembly (i.e. one in which the wheels are not orientable relative to the axle) at the rear of a sub-chassis and a wheel/axle assembly with individually-steerable wheels at the front of the sub-chassis. Penzotti (U.S. Pat. No. 5,246,242) describes a variation having two fixed axle assemblies on a sub-chassis. Both of these systems rely on relative movement between the trailer's main chassis and a sub-chassis due to turning for their action, and neither requires significant modification of the prime mover compared to a conventional one. This is advantageous. Both require provision for locking of the sub-chassis to the main chassis of the trailer in a straight-ahead condition for reversing purposes. Mitchell (PCT/GB97/02008) describes a comparatively complex system with two sets of individually steerable wheels and a fixed wheel/axle assembly on a sub-chassis, and having provision for providing different and selectable steering responses in forward and reverse travel.
In one aspect, the invention disclosed herein is in this class, as reliance is placed on the tendency of the trailer's wheels to continue moving forward as the front of the trailer is displaced laterally in a turn to control orientation of wheels on the trailer.
According to the invention there is provides a trailer for use as part of an articulated vehicle, the trailer including:
a main chassis pivotally connectable to a wheeled section of the vehicle immediately ahead of the trailer so that said wheeled section can articulate relative to said main chassis about a substantially upright first axis in the main chassis;
a sub-chassis having ground-engaging wheels mounted thereto, said sub-chassis being connected to the main chassis for free pivoting about a substantially upright second axis in the main chassis;
stop means adapted to define a maximum angle of said free pivoting by said sub-chassis away from a position of longitudinal alignment with said main chassis, said maximum angle being dependent on the positioning of said stop means relative to said main chassis; and
stop positioning means for automatically positioning said stop means relative to said main chassis in response to articulation of said wheeled section about said first axis so that said maximum angle is variable according to the positioning of said means.
In a preferred aspect, the trailer has a plurality of pairs of ground-engaging wheels longitudinally spaced apart on said sub-chassis and includes steering means responsive to relative rotation of said sub-chassis and said main chassis about said second axis for steering at least one said pair of wheels relatively to said sub-chassis in such a sense as to tend to align said sub-chassis longitudinally with said main chassis. This arrangement can further reduce the amount of scrubbing of tyres on a road surface during turns.
A said pair of steerable wheels may be mounted to a rigid axle assembly, said axle assembly being pivotally mounted to said sub-chassis and said pair of wheels being steerable by pivoting of said axle assembly about a substantially upright third axis in said sub-chassis. The said steering means preferably includes a first link connecting said axle assembly and said main chassis or a part secured to said main chassis.
Preferably, in use on a curved path the angle of pivoting of said sub-chassis about said second axis and away from a position of longitudinal d sub-chassis alignment with said main chassis is said maximum angle. That is the sub-chassis pivots to an angle at which further pivoting is prevented by the action of the stop means.
In one embodiment, the trailer further includes:
a yoke mounted to said main chassis and bearing against said stop means; and
connecting means whereby said yoke is connected to said sub-chassis and movable in said main chassis responsively to rotation of said sub-chassis about said second axis. Preferably, the yoke is mounted for substantially longitudinal movement in the main chassis and has a slide surface extending in a direction substantially transverse to the main chassis;
a slider is included in said stop means and mounted in said main chassis so as to pivot around said first axis in concert with said wheeled section pivoting about said first axis; and
said slide surface bears against said slider.
Still more preferably in this embodiment, the trailer includes two said yokes and two said connecting means each connecting means associated with one of said yokes and when the sub-chassis is aligned with the main chassis for straight-ahead travel, the slider is located substantially at a transverse midpoint of the main chassis and respective said slide surfaces of both yokes bear on said slider, and the connecting means, yokes and sub-chassis are so arranged that as one said yoke moves forward the other said yoke moves backward.
The or each said connecting means may include a second link pivotally connected to the yoke and to the sub-chassis.
In a second embodiment, the invention provides a trailer including:
a member arrange for movement in response to rotation of said sub-chassis about said second axis; and
movement transmitting means whereby said movement of said member causes a corresponding movement of a follower means,
and wherein said corresponding movement of said follower means is limited by said stop means. This embodiment may also, and preferably does, have at least one pair of its ground engaging wheels steerable by steering means as disclosed above.
It is particularly preferred that said movement transmitting means includes first and second hydraulic actuators operatively interconnected by hydraulic fluid conduits so that actuation of said first actuator by said movement of said member produces a corresponding movement by said second actuator of said follower means. There may be further included a vessel having an internal space in fluid communication with a hydraulic fluid conduit connecting said hydraulic actuators and means whereby the volume of said space increases as hydraulic fluid pressure in said space increases.
The trailer in this embodiment may include an elongate telescopic link having a predetermined minimum length when fully inwardly telescoped, said telescopic link when telescopic to said minimum length causing said movement of said member in response to said rotation of said sub-chassis in a particular direction. Preferably, said telescopic link is one of two such telescoping links respectively disposed to cause said movement of said member in response to said rotation of said sub-chassis in opposing first and second directions, and as one said link causes said movement of said member the other said link telescopically extends in length.
The stop means in this embodiment may include a cam arranged to rotate in said main chassis about said first axis and adapted to be operatively coupled to said wheeled section.
In any of the forms disclosed above, the trailer preferably further stop means for limiting to a fixed maximum value said angular rotation of said sub-chassis about said second axis and away from said position of alignment with said main chassis.
It is also preferred that the trailer include first locking means whereby when said sub-chassis is in longitudinal alignment with said main chassis and any angular deviation from longitudinal alignment of said wheeled section and said main chassis is less than a specified value said locking means is operable to hold said sub-chassis and said main chassis in longitudinal alignment. There may be provided a user-selectable mode of operation whereby said sub-chassis is maintained in longitudinal alignment with said main chassis for only so long as said angular deviation from longitudinal alignment of said wheeled section and said main chassis remains less than said specified value.
Second locking means may also be provided which for so long as a reverse gear of said articulated vehicle is engaged locks said sub-chassis and said main chassis at such relative angular deflection about said second axis as exists when reverse gear is engaged.
In a further aspect, the invention provides an articulated vehicle including a trailer in any of the forms disclosed above.
There is also provided apparatus for operating a ground wheel steering means of a trailer mountable to a fifth wheel assembly of an articulated vehicle, said fifth wheel having a slot in which a kingpin of said trailer is receivable and retainable, said apparatus including:
a member arranged to pivot about an axis of said kingpin;
means whereby said ground wheel steering means is operated responsively to pivoting of said member about said axis;
drive means secured to said member and which depend from said trailer and are receivable in said slot.
The invention will now be described in more detail by reference to the preferred embodiments, although without any intention to limit the scope of the invention. Reference is made to the following Figures, of which:
In the following description, the main inventive concept of a variable stop means applied to automatic steering of a sub-chassis on a trailer is described, first generally and then by reference to two detailed embodiments. Certain locking arrangements are then described. A particularly preferred form of sub-chassis is then described, having individually steerable axle assemblies. This is usable with either embodiment of the variable stop means. Finally a novel arrangements for connection of a trailer according to the invention to a prime mover's “fifth wheel” is described.
The vehicle 1 is shown in
Suppose now that the sub-chassis 20 is completely free to rotate about axis 23, and suppose further that the vehicle 15 is at first travelling straight ahead with the main chassis 18, the sub-chassis 20, and prime mover 16 longitudinally aligned, i.e. with longitudinal axes 24, 25 and 28 respectively, in line with each other.
The arrangement shown in
The value of angle 26′ which gives correct tracking in a steady established turn, as shown in
In the arrangement shown in
Wheel scrub during turning can be further alleviated, by combining the above invention with a different type of sub-chassis, which will be described in outline here and in detail later. This different sub-chassis type is also usable with other trailer steering arrangements and is an invention in itself, independently of the invention described above.
Through use of the different sub-chassis 33, rather than the sub-chassis 20, in combination with the variable stop means mentioned above (and described below) a larger reduction in wheel scrub can be achieved while still obtaining the improved tracking that the variable stop means can provide. This is because pure rolling, as opposed to combined rolling and sliding, of the trailer wheels 37, 38 and 39 is more nearly approachable.
Variable Stop Means
Variable stop means will be described using as an example the vehicle 15 shown in
(a) Fully Mechanical Variable Stop Means
Secured to the sub-chassis 20 via pivots 61 are two equal-length rods 62 a and 62 b. (The suffixes “a” and “b” here indicate separate components which are the same save for being oppositely located relative to the main chassis central axis 24. The same convention is used for other items in the following description.) The pivots 61 are symmetrically located on opposite sides of longitudinal axis 25 of the sub-chassis 20. The rods 62 a and 62 b are pivotally connected at pivots 67 to yokes 63 a and 63 b, respectively, and do not contact each other where they cross (see
Accordingly when prime mover 16 begins a right turn, radius arm 120 rotates clockwise, as seen from above by an observer on the main chassis 18, so that slider 65 moves left and forward (also as seen by the observer) as shown in
A right turn has been described above. It will be apparent that the symmetrical arrangement of components ensures similar operation during left hand turns.
A number of refinements to this basic scheme are provided for enhanced effectiveness. These will now be described.
In low-speed manoeuvring particularly, a driver may suddenly decrease the sharpness of a turn being executed by the prime mover 16. Very large forces between the slider surface 64 a (or 64 b) and slider 65 can then arise, as the sub-chassis 20 takes some travel distance to adjust to a new degree of turning. (This situation is analogous to the large increase in steering effort experienced by the driver of a motorcar when rapidly changing the radius of a turn at very low speeds.) To limit this effect, yokes 63 a and 63 b include identical resilient sections 68 a and 68 b respectively.
A first component 69 a slides telescopically on a co-axial second component 70 a and components 69 a and 70 a are urged apart by a coil spring 71 a between them. Rods 72 a are secured to component 69 a and free to slide within component 70 a. Stops 73 a on rods 72 a prevent components 69 a and 70 a actually separating. Spring 71 a is under a predetermined compression force (preload) when components 69 a and 70 a are as far apart as stops 73 a permit. In a sudden decrease of the tightness of a turn at a low forward travel speed, excessively large forces in the yoke 63 a do not develop, as its components 69 a and 70 a slide towards each other, compressing spring 71 a. As the turn continues, the sub-chassis 20 adjusts to a new position. During this adjustment process, angle 26 can temporarily exceed the angle 26′ that corresponds to any instantaneous position of the slider 65.
If on the other hand a sudden increase in the tightness of a turn is made, as can also happen particularly during low-speed manoeuvring, the slider 65 can cease to be in contact with slide surface 64 a (or 64 b), but the sub-chassis 20 then simply rotates further, following its natural tendency to roll straight ahead, until contact is regained. In this case, the slider 65 is kept oriented correctly relative to the slide surfaces 64 a and 64 b by a link 250 which is pivotally connected to an arm 251 on slider 65 and at pivot point 252 to main chassis 18, to form a parallelogram linkage.
The resilient sections 68 a and 68 b have another purpose. When the sub-chassis 20, the main chassis 18 and the prime mover 16 are aligned straight ahead, the springs 71 a and 71 b are slightly compressed, so that there is a small preload between surface 64 a and slider 65 and between surface 64 b and slider 65. This takes up clearances in the system, so that smooth operation is obtained without the manufacturing difficulties of avoiding clearances between the yokes 63 a and 63 b and slider 65.
The preloading of springs 71 a and 71 b has a consequence that must be dealt with. As a right turn (for example) is initiated from a straight-ahead configuration of the vehicle 15, slider 65 moves laterally so that it remains in contact with slide surface 64 a, but leaves contact with slide surface 64 b. The preload in spring 71 b thus causes face 64 b to move slightly forward until stops 73 b contact component 70 b. As the angle of turn increases and yoke 63 a moves forward, yoke 63 b moves back so that slide surface 64 b moves back. However, for very small angles of turn, the small forward movement of face 64 b due to relaxing of preload in spring 71 b can exceed the offsetting rearward movement of yoke 63 b, so that there is potential for interference between slider 65 and yoke 63 b as slider 65 returns to a central position. The opposite occurs in a left turn. This effect is avoided by a rocking latch 400 which is mounted to the main chassis 18 for pivotal movement about a horizontal pin 401 which is parallel to axis 24 of the trailer 17 and fixed in a transversely central position in trailer 17. Latch 400 is shown in phantom outline in
It is not desirable in practice for the angle 26′ between the axes 24 and 25 to become too large—30 degrees has been found a suitable absolute maximum value. Suitable mechanical stops (not shown) are therefore provided on main chassis 18 to limit left or right rotation of sub-chassis 20. However, these do not prevent the prime mover 16 taking up angles of articulation relative to the main chassis 18 which would otherwise lead to larger angles 26′ than the stops permit. In such cases, the slider 65 can simply cease to be in contact with the slide surface 64 a or 64 b. When the prime mover 16 returns to a more-nearly-straight-ahead position, slider 65 again contacts slide surface 64 a or 64 b.
(b) Mechanical/Hydraulic Variable Stop Means
This alternative embodiment will also be described by reference to vehicle 15 shown in
Sleeve members 412 a and 412 b are secured to sub-chassis 20 via pivots 413 a and 413 b, so that they can pivot about upright axes of rotation through pivots 413 a and 413 b. Except at the pivots 413 a and 413 b, sleeve members 412 a and 412 b are of tubular form. Rod members 414 a and 414 b are mounted to a clevis fitting (fork) 415 and are slideable within sleeve members 412 a and 412 b. Rod members 414 a and 414 b have stops 416 a and 416 b partway along their length which limit the distance they can penetrate into their respective sleeve members 412 a and 412 b.
Clevis fitting 415 is at the rear end of a slide 417 which is able to slide in a guide 418 fixed on the longitudinal centreline 24 of main chassis 18. Connected between the front end of slide 417 and a fitting 419 fixed on the longitudinal centreline 24 of the main chassis 18 is a hydraulic ram 420. As slide 417 moves forward, fluid in the head end of ram 420 is pumped into a tube 421 and fluid in a tube 422 is drawn into the rod end of ram 420. The reverse happens as slide 417 moves backward.
Referring now to
A slide 424 has a cam follower roller 425 on its forward end which bears against shaped edge 426 of cam plate 423. Slide 424 is able to slide within a guide 427 secured along the longitudinal centreline 24 of main chassis 18. Secured to the rear end of slide 424 is a hydraulic ram 428. Tubes 422 and 421 extend forward from ram 420 and are connected to the rod end and head ends respectively of ram 428.
A third hydraulic ram 429 is provided and is single-acting, with its head end connected to tube 421 between rams 420 and 428. The piston rod 430 of ram 429 is secured to a slider 431 which is able to slide along guide rods 432 secured to the main chassis 18. A compression force is maintained in piston rod 430 by preload in a coil spring 433 which extends between slider 431 and a plate 434 on main chassis 18. By this means, hydraulic fluid in subsystems 410 and 411 is pressurized enough for sliders 417 and 424 to be urged backward and forward, respectively and take up clearances in subsystems 410 and 411. Specifically, when the prime mover 16, main chassis 18 and sub-chassis 20 are aligned in the straight-ahead position, cam follower roller 425 is held in contact with edge 426 of cam plate 423, and slider 417 and rod members 414 a and 414 b are pushed backwards until stopped by engagement between stops 416 a and 416 b with sleeve members 412 a and 412 b, respectively.
Cam plate 423 is lobe-shaped, with varying radius about axis 19, so that as it rotates in concert with prime mover 16, away from the straight-ahead position to a turned position, cam follower roller 425 is able to move progressively further forward. Taking a right turn of vehicle 15 as an example, the natural tendency of sub-chassis 20 to roll straight ahead means that sleeve member 412 b pushes against stop 416 b, so that slider 417 moves forward and hydraulic fluid is pumped between ram 420 and ram 428. This results in slider 424 moving forward also, a movement limited by contact between roller 425 and cam plate 423. In this way, allowable rotation of sub-chassis 20 is limited to an angle 26′ (between axes 24 and 25) that varies with the angle between the prime mover 16 and main chassis 18.
Note that the degree of preload and the force per unit deflection (spring rate) of spring 433 are so chosen that during normal turning there is no significant tendency for hydraulic fluid displaced from ram 420 to be taken up by ram 429. However, circumstances such as sharp reductions of turning angle of the prime mover 16 at low speeds (as discussed above) do not lead to excess pressures in the hydraulic fluid, as ram 429 can take up fluid in these circumstances with a corresponding deflection of spring 433. Ram 429 and spring 433 are here providing the same function as resilient sections 68 a and 68 b of system 60. In an analogous way, a sharp increase of turning angle at low speeds simply causes roller 425 to separate from cam plate 423 temporarily. When hydraulic fluid; enters ram 429, line 422 requires make-up fluid. This can be provided in several ways. One is to connect the rod end of ram 429 to line 422 if rams 420, 428 and 429 have the same bore and rod diameters (not shown). Another is to vent line 422 to a reservoir maintained at a low pressure (hydraulic accumulator) (not shown). Rams 420, 428 and 429 could also be single acting.
It will be appreciated that sliders 417 and 424 could, instead of being hydraulically coupled as described above, be joined by a rod (not shown) extending along axis 24 of the main chassis 18, the rod having a resilient element therein (not shown) operating on the same principle as 68 a and 68 b. Such a system would be an alternative to system 60 and is within the scope of the invention.
Locking of Sub-chassis to Main Chassis of Trailer
This part of the disclosure will refer to vehicle 15 and variable stop system 60, but it is equally applicable to vehicle 29 and to the alternative variable stop system 410/411. It is desirable to provide for locking of sub-chassis 20 to the main chassis 18 in particular circumstances. High speed forward travel is an example where it can be desirable to have the sub-chassis 20 locked to the main chassis 18 with axes 24 and 25 aligned. In this situation, deviations from straight-ahead positions of the prime mover 16 and sub-chassis 20 are very limited.
Tongue 75 slides in a guide 79 fixed to main chassis 18, and is for locking sub-chassis 20 in the straight-ahead position, by entering cooperating recess 80 in sub-chassis 20.
An air valve 81 fixedly mounted to the main chassis 18 is operable by a formation 82 on a cam plate 83 secured to sub-chassis 20, whenever the axes 24 and 25 are within a small predetermined angle of perfect alignment. A further air valve 84 is also fixedly mounted to the main chassis 18 (see
It is of course possible by routine means to provide that once sub-chassis 20 is locked in the straight-ahead position as above, a deliberate operator input (other than mere steering) is required for unlocking. Thus, the vehicle 15 can if required be made to operate in the same way as the conventional vehicle 1. A user may in this way lock sub-chassis 20 in the straight-ahead position for reversing.
Irrespective of whether axes 24 and 25 are aligned, sub-chassis 20 should be automatically locked to main chassis when the prime mover 16 is in reverse gear. Locking segments 76 a and 76 b are provided for this. When actuated by actuators 78 a and 78 b, they pivot rearward so that at least one engages an arcuate rack 87 on sub-chassis 20.
Reversing can thus be done with the sub-chassis 20 and main chassis 18 aligned, if required, or with sub-chassis 20 locked in an articulated position, for example for tight reverse manoeuvres.
Alternatively, either or both of valves 81 and 84, 88 a may be replaced by electric switches or other suitable transducers and the above functionality achieved by routine means using a suitable combination of electric/electronic and pneumatic circuitry. In a particularly simple arrangement, the reversing light circuit can be used to cause locking segments 76 a and 76 b to operate. Alternatively, a separate and dedicated circuit may be used.
Alternative Sub-chassis Arrangement
The sub-chassis 33 of the vehicle 29 will now be described, in particular the means whereby the rigid axles 34 and 36 are aligned responsively to pivoting of the sub-chassis 33 relative to main chassis 32, so that wheels 37 and 39 “steer” in the correct sense.
Central, non-steering rigid axle 35 is mounted transversely to the sub-chassis 33 in conventional manner as known in the art, i.e. with a resilient suspension to allow substantially vertical movement of axle 35 for absorption of road unevenness, but with the axle 35 always remaining substantially transverse to the sub-chassis 33. Axle 35 is shown (
The steerable rigid axles 34 and 36 and their wheels 37 and 39 respectively are mounted in essentially the same way to frames 106 and 107 respectively as axle 35 is mounted to sub-chassis 33. Frames 106 and 107 are mounted beneath sub-chassis 33 and are pivotable about upright axes 108 and 109 in the sub-chassis 33, for steering orientation of axles 34 and 36 and wheels 37 and 39. The mounting of axles 34 and 36 to frames 106 and 107 is by the same means as that of axle 35 to sub-chassis 33, namely via leaf springs 150 and spring/damper units 151—see
Links 110 and 111 respectively connect frames 106 and 107 to the main chassis 32. Links 110 and 111 connect pivots 100 and 101 secured to frames 106 and 107 respectively to pivots 102 and 103 respectively on main chassis 32. By suitable choice of locations of pivots 100 and 101 on frames 106 and 107 and pivots 102 and 103 on main chassis 32, for example as shown in
In selecting pivot locations for the links 110 and 111, it is important to ensure that, as sub-chassis 33 pivots, the angle between sub-chassis 33 and main chassis 32 is in fact limited by the variable stop means 410/411 (or 60). If the angles between axes 40 and 41, and 41 and 42, (see
Connection of Prime Mover to Variable Stop Means
The variable stop means (system 60 or 410/411) are operated by a connection between the prime mover (16 or 30) and main trailer chassis (18 or 32). This will now be described, firstly by reference to system 60.
As best seen in
A drive pin 118 parallel to the king pin 116 passes up through an arcuate slot 119 in the skid plate 113, and is secured to radius arm 120 which is mounted to, and free to rotate about, an upper part of the king pin 116 and lies between the upper plate 112 and the skid plate 113. The drive pin 118 is secured to fifth wheel 115 of prime mover 16 in a manner described below so that as the prime mover 16 pivots about the king pin 116, the drive pin 118 revolves in concert with prime mover 16 around king pin 116. The arcuate slot 119 is centred on the king pin 116 and is long enough to accommodate the maximum permitted degree of relative articulation of the trailer 17 and prime mover 16.
Slider 65 is mounted to an upper extension of the pin 118, and is free to rotate around it.
For the alternative system 410/411, a simpler but similar arrangement is provided—see
The manner in which the drive pin 118 (or 436) is secured in a fixed position relative to the fifth wheel 115 will now be described.
Secured to the drive pin 118 at its lower end is a slider 552 which is free to slide in a cooperating slot 553 in a wedge member 554. The direction in which the slider 552 is free to slide in member 554 is indicated by arrow “z” in
In this way, the trailer 17 carries all the main mechanical components specific to steering of the rear sub-chassis 20, and the prime mover 16 can be conventional, with no major mechanical modification required for operation with the inventive trailer 17 (other than provision of a compressed air supply for the pneumatic components and minor pneumatic and/or electric components described above). This is an important practical advantage. The tapered section 559 of the wedge member 554 may (and ideally does) taper in such a way as to match the taper of the tapered slot 123 in fifth wheel 115. However, although the width of the parallel-sided slot 122 is standardized, various tapers are used in the tapered slots (such as 123) of fifth wheels, and it is desirable for one wedge member to be usable with a range of fifth wheels. To this end, the tapered section 559 of the wedge member 554 may have a taper corresponding to the maximum taper expected in practice, yet still be usable with fifth wheels having more narrowly tapered slots because the spring 557 causes the wedge member 554 to be forced as far forward in the fifth wheel 115 as it can go. The parallel-sided front section 560 is still received and firmly held in the slot 122. The variation which can be accommodated in practice depends on the need for the parallel-sided front section 560 to be received far enough into the slot 122. This method of provision of a steering “input” to a trailer without any requirement for modification of its tractor is inventive in itself.
It is of course possible to remove wedge member 554 from the slider 552 by removing plate 555 and simply sliding it off, and to then slide on to slider 552 a new wedge member 554 of different taper, compress the spring 557 and replace plate 555.
Many variations to the above embodiments may be made without departing from the spirit and scope of the invention.
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|AU3554989B||Title not available|
|AU4627193A||Title not available|
|AU4805385B||Title not available|
|AU7365987A||Title not available|
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|1||Derwent Abstract Accession No. 84-261914/42, Class Q22 SU 1074755 A, Feb. 23, 1984.|
|2||Derwent Abstract Accession No. 87-333548/47, Class Q22 SU 1303478 A, Apr. 15, 1987.|
|3||Derwent Abstract Accession No. 90-229914/30, Class Q22 SU 1533932 A, Jan. 7, 1990.|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US8335607||Feb 12, 2010||Dec 18, 2012||Ronald A. Gatten||Method and apparatus for linking electric drive vehicles|
|US8770601 *||Jul 6, 2010||Jul 8, 2014||Compagnie Generale Des Etablissements Michelin||Vehicle comprising at least two axles, the wheels of which are parallel|
|US8909426 *||Dec 23, 2011||Dec 9, 2014||Ford Global Technologies||Trailer path curvature control for trailer backup assist|
|US9238483||Apr 21, 2014||Jan 19, 2016||Ford Global Technologies, Llc||Trailer backup assist system with trajectory planner for multiple waypoints|
|US20060261572 *||May 19, 2004||Nov 23, 2006||Armando Biondi||Pneumatic cylinder device for trailer or semitrailer vehicles|
|US20090032273 *||Jun 19, 2008||Feb 5, 2009||Klaus Hahn||Implement/vehicle steering control system and method|
|US20110202212 *||Feb 12, 2010||Aug 18, 2011||Gatten Ronald A||Method and apparatus for linking electric drive vehicles|
|US20120187645 *||Jul 6, 2010||Jul 26, 2012||Michelin Recherche Et Technique S.A.||Vehicle comprising at least two axles, the wheels of which are parallel|
|US20120271515 *||Dec 23, 2011||Oct 25, 2012||Douglas Scott Rhode||Trailer path curvature control for trailer backup assist|
|U.S. Classification||280/426, 280/419, 280/423.1, 280/400, 280/442, 280/407.1|
|International Classification||B62D13/02, B62D53/06, B62D13/00|
|May 30, 2003||AS||Assignment|
Owner name: GAYAT PTY LTD., AUSTRALIA
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:ATLEY, KERRY;REEL/FRAME:014311/0902
Effective date: 20030527
|Oct 7, 2004||AS||Assignment|
Owner name: TRACKAXLE PTY LTD, AUSTRALIA
Free format text: CHANGE OF NAME;ASSIGNOR:GAYAT PTY LTD;REEL/FRAME:015867/0179
Effective date: 20040120
|Dec 27, 2010||REMI||Maintenance fee reminder mailed|
|May 22, 2011||LAPS||Lapse for failure to pay maintenance fees|
|Jul 12, 2011||FP||Expired due to failure to pay maintenance fee|
Effective date: 20110522